Supercoupling between heavy-hole and light-hole states in nanostructures

Luo, Jun-Wei; Bester, Gabriel; Zunger, Alex

doi:10.1103/physrevb.92.165301

Cited by 41 publications

(43 citation statements)

References 41 publications

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“…It is well established that the valence band is very sensitive to the reduced QD symmetry, which alters the pure heavyhole (HH) character [17][18][19] and mixes the HH with the light hole state (LH) states. We can write the hole states as a linear combination of HH and LH as and…”

Section: Introductionmentioning

confidence: 99%

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Dark-bright exciton coupling in asymmetric quantum dots

et al. 2018

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Section: Introductionmentioning

confidence: 99%

“…|β| is typically in the range of 0.1 to 0.7 (see, for example Ref. [25]), when the dominant contribution is given by the strain [19].…”

Section: Introductionmentioning

confidence: 99%

Dark-bright exciton coupling in asymmetric quantum dots

et al. 2018

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“…Ψ e and Ψ h denote the envelope functions for the electron and hole, respectively. not prevent heavy-hole-light-hole coupling 20,21 . Heavy-hole-light-hole coupling is an experimental fact [22][23][24][25] , revealed by deviations in the optical selection rules from the heavy-hole limit.…”

mentioning

confidence: 99%

Decoupling a hole spin qubit from the nuclear spins

Prechtel¹,

Kuhlmann²,

Houel³

et al. 2016

Nature Mater

107

106

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A huge effort is underway to develop semiconductor nanostructures as low noise hosts for qubits. The main source of dephasing of an electron spin qubit in a GaAs-based system is the nuclear spin bath 1-3 . A hole spin may circumvent the nuclear spin noise 4 . In principle, the nuclear spins can be switched off for a pure heavy-hole spin 4-6 . In practice, it is unknown to what extent this ideal limit can be achieved. A major hindrance is that p-type devices are often far too noisy. We investigate here a single hole spin in an InGaAs quantum dot embedded in a new generation of low-noise p-type device. We measure the hole Zeeman energy in a transverse magnetic field with 10 neV resolution by dark state spectroscopy as we create a large transverse nuclear spin polarization. The hole hyperfine interaction is highly anisotropic: the transverse coupling is < 1% of the longitudinal coupling. For unpolarized, randomly fluctuating nuclei, the ideal heavy-hole limit is achieved down to neV energies; equivalently dephasing times up to a µs. The combination of large T * 2 and strong optical dipole 3,7-11 make the single hole spin in a GaAs-based device an attractive quantum platform.A localized, single spin is a small and fast qubit. The exchange interaction between neighbouring spins facilitates two-qubit operations 12 . Implementation in a semiconductor benefits from advanced semiconductor heterostructures and nano-fabrication; implementation in a GaAs-based heterostructure, the cleanest and most versatile semiconductor system, by trapping the spin to a quantum dot also facilitates the creation of a spin-photon interface. A stumbling block is that the nuclear spins in the quantum dot lead to a rapid loss of electron spin coherence (both T 2 and T * 2 processes). This has motivated interest in isotopically-pure silicon, a nuclear spin-free host 13 . However, the large effective mass of a conduction electron in Si demands much smaller structures and lower operating temperatures; the valley degeneracy is an additional complication 14 ; the strong

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“…In our model, this mixing is controlled by ∆ lh , an effective energy splitting between heavy-holes and light-holes. This simple parameter can indeed describe more complex effects such as a coupling of the confined heavy-hole with ground state light-holes in the barriers 46 or effective reduction of heavy-hole/light-hole splitting due to a presence of a dense manifold of heavyhole like QD states lying between the confined heavy-hole and light-hole levels 47 . From this modelling we deduce that for a hole confined in small Cd x Zn 1−x Te alloy QDs, the Mn-hole flip-flop time τ f f can be easily bellow 2 ns for an effective heavy-hole/light-hole splitting ∆ lh =15 meV and an energy separation in the meV range, typical for the Mn-hole spin splitting in magnetic QDs.…”

Section: Modelling Of the Dynamics Of The Hybrid Mn-hole Spinmentioning

confidence: 99%

Resonant photoluminescence and dynamics of a hybrid Mn hole spin in a positively charged magnetic quantum dot

2017

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We analyze, through resonant photoluminescence, the spin dynamics of an individual magnetic atom (Mn) coupled to a hole in a semiconductor quantum dot. The hybrid Mn-hole spin and the positively charged exciton in a CdTe/ZnTe quantum dot forms an ensemble of Λ systems which can be addressed optically. Auto-correlation of the resonant photoluminescence and resonant optical pumping experiments are used to study the spin relaxation channels in this multilevel spin system. We identified for the hybrid Mn-hole spin an efficient relaxation channel driven by the interplay of the Mn-hole exchange interaction and the coupling to acoustic phonons. We also show that the optical Λ systems are connected through inefficient spin-flips than can be enhanced under weak transverse magnetic field. The dynamics of the resonant photoluminescence in a p-doped magnetic quantum dot is well described by a complete rate equation model. Our results suggest that long lived hybrid Mn-hole spin could be obtained in quantum dot systems with large heavy-hole/light-hole splitting.

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Supercoupling between heavy-hole and light-hole states in nanostructures

Cited by 41 publications

References 41 publications

Dark-bright exciton coupling in asymmetric quantum dots

Dark-bright exciton coupling in asymmetric quantum dots

Decoupling a hole spin qubit from the nuclear spins

Resonant photoluminescence and dynamics of a hybrid Mn hole spin in a positively charged magnetic quantum dot

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